Speed reduction device, power steering apparatus, and vehicle

Abstract

A speed reduction device (3), comprising a three-stage transmission mechanism (10). The three-stage transmission mechanism (10) comprises a first-stage transmission mechanism (200), a second-stage transmission mechanism (300), and a third-stage transmission mechanism (400). The first-stage transmission mechanism (200) is a gear set structure, the second-stage transmission mechanism (300) is a planetary gear set structure, and the third-stage transmission mechanism (400) is a planetary gear set structure. Also provided are a power steering apparatus (2) and a vehicle (1). The speed reduction device comprises a three-stage transmission mechanism, and the second-stage transmission mechanism and the third-stage transmission mechanism of the three-stage transmission mechanism are respectively planetary gear set structures having a large transmission ratio, such that the speed reduction device has good speed reduction and torque increase effects, and the number of speed reduction stages is small, facilitating increase of the response speed of the speed reduction device, thereby reducing the steering errors of the power steering apparatus and the vehicle.

Description

Deceleration device, power steering system and vehicle

[0001] This application claims priority to Chinese patent applications filed on July 31, 2024, with application number 202411049459.0, and filed on January 23, 2025, with application number 202510113807.4, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of power steering technology, and more specifically to deceleration devices, power steering systems, and vehicles. Background Technology

[0003] Currently, electric steering systems for commercial vehicles include a main reduction system that increases torque and reduces speed for the motor output. This main reduction system uses multi-stage reduction to achieve a better deceleration and torque increase effect. However, the more reduction stages there are, the slower the response speed of the main reduction system and the greater the steering error. Summary of the Invention

[0004] In a first aspect, this application provides a speed reduction device, comprising:

[0005] Three-stage transmission mechanism;

[0006] The three-stage transmission mechanism includes a first-stage transmission mechanism, a second-stage transmission mechanism, and a third-stage transmission mechanism; the first-stage transmission mechanism is a gear set structure, the second-stage transmission mechanism is a planetary gear set structure, and the third-stage transmission mechanism is a planetary gear set structure.

[0007] In some embodiments, the deceleration device further includes:

[0008] A first housing, wherein the third-stage transmission mechanism is disposed within the first housing;

[0009] A second housing, wherein the first-stage transmission mechanism and the second-stage transmission mechanism are disposed; and

[0010] The first housing and the second housing are detachably connected, and the input end of the third-stage transmission mechanism and the output end of the second-stage transmission mechanism are detachably connected.

[0011] In some embodiments, the input end of the first-stage transmission mechanism is used to connect to the drive motor; the input end of the second-stage transmission mechanism is connected to the output end of the first-stage transmission mechanism.

[0012] In some embodiments, the first-stage transmission mechanism includes at least a first-stage output wheel, which is used to connect to a drive motor and to connect to the input end of the second-stage transmission mechanism.

[0013] In some embodiments, the primary transmission mechanism further includes a primary key connection mechanism, which is disposed at the middle of the primary output wheel and is used to connect the primary output wheel and the second-stage transmission mechanism.

[0014] In some embodiments, the second-stage transmission mechanism includes:

[0015] The second-stage sun gear is connected to the first-stage transmission mechanism so that the first-stage transmission mechanism drives the second-stage sun gear to rotate.

[0016] Multiple planetary gear assemblies are sequentially distributed along the circumference of the secondary sun gear and mesh with the secondary sun gear respectively; and

[0017] A secondary internal gear ring, wherein the plurality of planetary gear assemblies are at least partially located in the secondary internal gear ring and respectively mesh with the secondary internal gear ring.

[0018] In some embodiments, the second-stage transmission mechanism includes:

[0019] A secondary sun gear is connected to the primary key connection mechanism, so that the primary output wheel drives the secondary sun gear to rotate through the primary key connection mechanism;

[0020] Multiple planetary gear rear wheels are provided, and the planetary gear rear wheels are located close to the first-stage transmission mechanism, and the planetary gear rear wheels mesh with the second-stage sun gear;

[0021] Multiple planetary gear front wheels are positioned close to the third-stage transmission mechanism, and the front planetary gears are coaxially fixed with their corresponding rear planetary gears.

[0022] A secondary internal gear ring is fixedly connected to the second housing, and the front planetary gear is disposed in the secondary internal gear ring and meshes with the secondary internal gear ring.

[0023] In some embodiments, the rear planetary gear is provided with a connecting groove, and the front planetary gear is provided with a connecting shaft. The connecting shaft is inserted into the connecting groove to achieve coaxial and relative fixation between the front planetary gear and the corresponding rear planetary gear.

[0024] In some embodiments, the second-stage transmission mechanism further includes:

[0025] The secondary rear support is disposed between the primary output wheel and the planetary gear rear wheel; and

[0026] A secondary front support is provided, which is disposed between the planetary gear front wheel and the third-stage transmission mechanism, and is connected to the secondary rear support.

[0027] In some embodiments, the secondary transmission mechanism further includes a plurality of secondary support connecting bolts, which pass through the rear planetary gear and the front planetary gear, and the secondary rear support and the secondary front support are connected by the secondary support connecting bolts.

[0028] In some embodiments, a secondary support radial bearing and a secondary support axial bearing are provided between the primary output wheel and the secondary rear support, and the primary output wheel supports the rotation of the secondary rear support.

[0029] In some embodiments, a secondary sun gear bearing is provided between the secondary sun gear and the secondary front support, and the secondary front support supports the rotation of the secondary sun gear.

[0030] In some embodiments, the secondary front bracket is detachably connected to the input end of the third-stage transmission mechanism, so that the input end of the third-stage transmission mechanism and the output end of the second-stage transmission mechanism are detachably connected.

[0031] In some embodiments, the second-stage transmission mechanism includes:

[0032] A secondary key connection mechanism is provided, which is located in the middle of the secondary front bracket and is used to connect the third-stage transmission mechanism so that the secondary front bracket and the input end of the third-stage transmission mechanism can be detachably connected.

[0033] In some embodiments, the secondary transmission mechanism further includes:

[0034] The transmission gear is located on the side of the secondary front bracket facing the third-stage transmission mechanism, and the transmission gear is a hyperbolic helical gear or a spur gear.

[0035] In some embodiments, it also includes:

[0036] The steering input mechanism is used to connect to the steering device externally and to connect to the secondary front support internally, driving the secondary front support to rotate.

[0037] In some embodiments, the axis of the steering input mechanism is perpendicular to the axis of the secondary front support.

[0038] In some embodiments, the steering input mechanism includes:

[0039] An input shaft, used for external connection to a steering device;

[0040] A torsion bar, the first end of which is connected to the input shaft;

[0041] An input gear, which connects to the secondary front support, and the second end of the torsion bar is connected to the input gear; and

[0042] An angle sensor is sleeved on the outside of the input shaft and is used to detect the relative rotation angle between the input shaft and the input gear.

[0043] In some embodiments, the input shaft is a hollow shaft, the torsion bar is disposed inside the input shaft, and the first end of the torsion bar is connected to the input shaft via an input shaft pin.

[0044] In some embodiments, it also includes:

[0045] The main support is disposed between the second-stage transmission mechanism and the third-stage transmission mechanism, and is fixedly connected to the second housing.

[0046] In some embodiments, the input gear of the steering input mechanism meshes with the secondary front support, and the axial end of the input gear is connected to the main support.

[0047] In some embodiments, the third-stage transmission mechanism includes:

[0048] The third-stage sun gear is detachably connected to the second-stage front bracket, and the third-stage sun gear can be driven by the second-stage front bracket;

[0049] Multiple third-stage planetary gears, wherein the third-stage planetary gears mesh with the third-stage sun gear; and

[0050] A three-stage internal gear ring is fixedly connected to the first housing, and a three-stage planetary gear is disposed in the three-stage internal gear ring and meshes with the three-stage internal gear ring.

[0051] In some embodiments, the third-stage sun gear is connected to the second-stage key connection mechanism of the second-stage front bracket, so that the third-stage sun gear and the second-stage front bracket are detachably connected.

[0052] In some embodiments, a secondary support main bearing is provided between the secondary front support and the main support;

[0053] A main bearing for the third-stage sun gear is provided between the main support and the third-stage sun gear, and the main support supports the rotation of the third-stage sun gear.

[0054] In some embodiments, the third-stage transmission mechanism further includes:

[0055] The third-stage rear support is disposed between the second-stage transmission mechanism and the third-stage planetary gear;

[0056] A three-stage front support is disposed at the output end of the third-stage transmission mechanism, and the three-stage front support is fixedly connected to the three-stage rear support; and

[0057] The output shaft is connected to the three-stage front bracket and can be driven to rotate by the three-stage front bracket.

[0058] In some embodiments, the third-stage transmission mechanism further includes:

[0059] A third-stage planetary bearing, wherein the third-stage planetary bearing is disposed within the third-stage planetary gears; and

[0060] A three-stage planetary shaft is disposed within a three-stage planetary bearing to support the rotation of the three-stage planetary bearing.

[0061] In some embodiments, the first end of the third-stage planetary shaft is connected to the third-stage rear support, and the second end of the third-stage planetary shaft is connected to the third-stage front support, thereby fixing the third-stage front support and the third-stage rear support relatively to each other.

[0062] In some embodiments, a third-stage rear support main bearing is provided between the main support and the third-stage rear support;

[0063] An output shaft auxiliary bearing is provided between the third-stage sun gear and the third-stage front support; and

[0064] An output shaft main bearing is provided between the third-stage front bracket and the first housing.

[0065] In some embodiments, the three-stage internal gear ring and the first housing are an integral structure.

[0066] In some embodiments, it also includes:

[0067] The third housing is detachably connected to the second housing, and the first-stage output wheel is supported and rotated by the third housing.

[0068] In some embodiments, the primary output wheel includes:

[0069] A primary output gear ring, wherein the primary output gear ring is used to connect to the motor control mechanism; and

[0070] A primary output gearbox base is fixedly connected to the primary output gear ring. The primary output gearbox base is used to connect the third housing and the secondary sun gear respectively.

[0071] In some embodiments, the primary key connection mechanism is located in the middle of the primary output gearbox base.

[0072] In some embodiments, a primary output wheel main bearing is provided between the third housing and the primary output gear base, and the third housing supports the rotation of the primary output wheel.

[0073] In some embodiments, the first-stage transmission mechanism includes a first-stage idler wheel and a first-stage input gear. The first-stage idler wheel meshes with the first-stage output wheel, and the first-stage input gear meshes with the first-stage idler wheel. The first-stage input gear is used to connect to the motor control mechanism.

[0074] In some embodiments, the first-stage transmission mechanism includes two first-stage idler gears and two first-stage input gears, the two first-stage idler gears respectively meshing with the first-stage output gear, and the two first-stage input gears meshing with the two first-stage idler gears in a one-to-one correspondence.

[0075] In some embodiments, the two primary input gears are used to connect the two motor control mechanisms in a one-to-one correspondence; or...

[0076] The two primary input gears are used to connect to one of the motor control mechanisms.

[0077] In some embodiments, the first-stage transmission mechanism includes a first-stage input gear that meshes with the first-stage output gear, and the first-stage input gear is used to connect to the motor control mechanism.

[0078] In some embodiments, the first-stage transmission mechanism includes one first-stage idler gear and two first-stage input gears, the two first-stage input gears respectively meshing with one first-stage idler gear.

[0079] In some embodiments, the primary output wheel is a worm gear or a helical gear.

[0080] In some embodiments, the second-stage transmission mechanism is a harmonic reduction mechanism, a rotary vector reduction mechanism, or a pinwheel reduction mechanism; and / or,

[0081] The third-stage transmission mechanism is a harmonic deceleration mechanism, a rotary vector deceleration mechanism, or a pinwheel deceleration mechanism.

[0082] Secondly, this application provides a power steering system, comprising:

[0083] The speed reduction device described above includes a three-stage transmission mechanism, comprising a first-stage transmission mechanism, a second-stage transmission mechanism, and a third-stage transmission mechanism; the first-stage transmission mechanism is a gear set structure, the second-stage transmission mechanism is a planetary gear set structure, and the third-stage transmission mechanism is a planetary gear set structure.

[0084] The motor control mechanism is connected to the first-stage transmission mechanism of the reduction device and is used to drive the first-stage transmission mechanism of the reduction device to rotate.

[0085] In some embodiments, the motor control mechanism includes:

[0086] One or two drive motors, each drive motor including a motor shaft connected to the first-stage transmission mechanism; and

[0087] The drive motor is fixedly connected to the second housing of the reduction gear.

[0088] In some embodiments, the motor control mechanism further includes:

[0089] The inner ring of the coupling is connected to both the motor shaft and the first-stage input gear of the reduction gear; and

[0090] A damping buffer pad is disposed between the inner ring of the coupling and the first-stage input gear.

[0091] Thirdly, this application provides a vehicle including a power steering system as described above, the power steering system comprising:

[0092] The speed reduction device described above includes a three-stage transmission mechanism, comprising a first-stage transmission mechanism, a second-stage transmission mechanism, and a third-stage transmission mechanism; the first-stage transmission mechanism is a gear set structure, the second-stage transmission mechanism is a planetary gear set structure, and the third-stage transmission mechanism is a planetary gear set structure.

[0093] The motor control mechanism is connected to the first-stage transmission mechanism of the reduction gear and is used to drive the reduction gear.

[0094] In this embodiment, by including a three-stage transmission mechanism in the deceleration device, and having the second and third stages of the three-stage transmission mechanism as planetary gear sets with large transmission ratios, the deceleration device can achieve a good deceleration and torque amplification effect while having fewer deceleration stages. This is beneficial for improving the response speed of the deceleration device and thereby reducing the steering error of the power steering system and the vehicle. Attached Figure Description

[0095] The following drawings, illustrating embodiments of this application, are incorporated herein by reference and are used to understand this application. The drawings illustrate embodiments of this application and their descriptions, serving to explain the principles of this application. In the drawings,

[0096] Figure 1 is a schematic diagram of a prior art speed reduction device;

[0097] Figure 2 is a perspective view of a power steering system provided according to some embodiments of this application;

[0098] Figure 3 is an exploded view of a power steering system provided according to some embodiments of this application;

[0099] Figure 4 is an exploded view of a speed reduction device provided according to some embodiments of this application;

[0100] Figure 5 is an exploded view of a speed reduction device provided according to some embodiments of this application;

[0101] Figure 6 is a perspective sectional view of a deceleration device provided according to some embodiments of this application;

[0102] Figure 7 is a perspective sectional view of a first-stage transmission mechanism provided according to some embodiments of this application;

[0103] Figure 8 is a perspective sectional view of a first-stage deceleration mechanism provided according to some embodiments of this application;

[0104] Figure 9 is an exploded view of a second-stage transmission mechanism provided according to some embodiments of this application;

[0105] Figure 10 is a perspective view of a secondary planetary gear according to some embodiments of this application;

[0106] Figure 11 is a cross-sectional view of a steering input mechanism provided according to some embodiments of this application;

[0107] Figure 12 is a cross-sectional view of a steering input mechanism provided according to some embodiments of this application;

[0108] Figure 13 is an exploded view of a third-stage transmission mechanism provided according to some embodiments of this application;

[0109] Figure 14 is a perspective view of a motor input mechanism provided according to some embodiments of this application;

[0110] Figure 15 is a schematic diagram of a speed reduction device provided according to some embodiments of this application;

[0111] Figure 16 is a schematic diagram of a speed reduction device provided according to some embodiments of this application;

[0112] Figure 17 is a schematic diagram of a power steering system provided according to some embodiments of this application;

[0113] Figure 18 is a schematic diagram of a power steering system provided according to some embodiments of this application;

[0114] Figure 19 is a schematic diagram of a power steering system provided according to some embodiments of this application;

[0115] Figure 20 is a schematic diagram of a power steering system provided according to some embodiments of this application;

[0116] Figure 21 is a structural schematic diagram of a vehicle provided according to some embodiments of this application.

[0117] Explanation of reference numerals in the attached drawings: 1-Vehicle; 2-Power steering gear; 3-Reduction gear; 10-Three-stage transmission mechanism; 100-Steering gear housing assembly; 101-First housing; 102-Second housing; 103-Third housing; 104-Fourth housing; 105-Main bracket; 106-Sealing gasket; 107-Rear housing seal ring; 108-Output shaft seal ring; 110-Input shaft seal ring; 112-Second connecting bolt; 113-Connecting gasket; 114-First connecting bolt; 115-Mounting hole; 131-Flange cylindrical surface; 200-First-stage transmission mechanism; 201-First-stage input gear; 202-First-stage idler gear; 203-First-stage output gear ring; 204-First-stage output gear base; 205-First-stage input gear bearing; 206-First-stage idler gear bearing; 207-First-stage idler gear shaft; 208-First-stage output gear main bearing; 209-Spring washer; 210-Third connecting bolt; 211-First-stage key connection mechanism; 220-First-stage output gear; 230-Second-stage support first support surface; 231-Second-stage support second support surface; 232-Second-stage connecting spline internal spline; 233-First-stage main bearing outer ring; 300 - Second-stage transmission mechanism; 301 - Second-stage support radial bearing; 302 - Second-stage support axial bearing; 303 - Second-stage sun gear; 304 - Rear planetary gear; 305 - Front planetary gear; 306 - Second-stage internal gear ring; 307 - Second-stage rear support; 308 - Second-stage front support; 309 - Second-stage support connecting column; 310 - Second-stage support main bearing; 311 - Second-stage support connecting bolt; 312 - Second-stage planetary shaft; 313 - Second-stage planetary radial bearing; 314 - Second-stage planetary main bearing; 315 - Second-stage planetary axial bearing; 316 - Second-stage sun gear bearing; 317 - Second-stage key connection mechanism; 318 - Transmission gear; 319 - Planetary gear assembly; 332 - Second-stage connecting spline external spline; 333 - Second-stage support main bearing inner ring; 334 - Second-stage support main bearing outer ring; 335 - Bearing housing; 341 - Connecting groove; 351 - Connecting shaft; 400 - Third-stage transmission mechanism; 401 - Third-stage internal gear ring; 402 - Third-stage planetary gear; 403 - Third-stage sun gear; 404 - Third-stage rear support; 405 - Third-stage front support; 406 - Third-stage planetary shaft; 407 - Third-stage planetary bearing; 408 - Bearing; 409 - Third-stage sun gear main bearing; 410 - Output shaft auxiliary bearing; 411 - Output shaft main bearing; 412 - Countersunk screw; 413 - Third-stage planetary shaft pressure plate; 414 - Third-stage support connecting column; 415 - Screw; 416 - Output shaft; 500 - Motor and electrical control mechanism; 501 - Drive motor; 502 - First-stage input gear auxiliary bearing; 503 - Coupling inner ring; 504 - Damping buffer pad; 505 - Bearing bracket; 506 - Motor sealing ring; 507 - Motor connecting bolt; 510 - Motor shaft; 600 - Steering input mechanism; 601 - Input shaft pin; 602 - Torsion bar seal; 603 - Input shaft;604 - Input shaft main bearing; 605 - Angle sensor; 606 - Torsion bar bushing; 607 - Input gear main bearing; 608 - Torsion bar; 609 - Input gear; 610 - Input gear auxiliary bearing; 611 - Input gear shim; 700 - Front part of reduction gear; 800 - Rear part of reduction gear. Detailed Implementation

[0118] As shown in Figure 1, the existing power steering system contains two reduction systems: an angular reduction system and a main reduction system. The angular reduction system increases torque and reduces speed from the steering wheel input, while the main reduction system increases torque and reduces speed from the motor output. Both reduction systems share a fourth-stage reduction mechanism. The steering system also features an independent input shaft flexibly connected to the input component of the input-stage reduction mechanism via a torsion bar spring. The upper and lower magnetic rings of the angle sensor are fixed to the input shaft and the input component of the input-stage reduction mechanism, respectively. Due to the input torque and the counter-torque, the torsion bar spring undergoes torsional deformation, resulting in a relative angular deflection between the input shaft and the input-stage reduction mechanism. This angle value is detected by the angle sensor, which transmits the signal to the controller. The controller executes a predetermined power steering strategy, sending a signal to the power steering motor to output the power steering torque and speed. The magnitude of the relative angle θ measured by the sensor determines the magnitude of the power steering torque. The sensitivity of this value determines the accuracy of the signal that the sensor can measure and transmit to the controller.

[0119] When the output shaft experiences a resistance torque Mz greater than the steering torque Ma during steering, a tendency for reverse rotation will occur. The angular reduction system generates a reverse rotation torque Mr = (Mz - Ma), which overcomes the system's inherent reverse transmission resistance torque Md and is transmitted to the torsion bar spring via a reverse speed-increasing and torque-reducing process. The reverse rotation torque received by the torsion bar spring is Mt = Mr / ia - Md, = (Mz - Ma) / ia - Md. Under the action of the torsional stiffness K of the torsion bar spring and the input torque Mi, the angle deflection is: θr = (Mt - Mi) / K = [(Mz - Ma) / ia - Md - Mi] / K ①;

[0120] When active steering is required, the angle deflection is: θf=[Mi-(Mz-Ma) / ia-Md] / K ②;

[0121] From the two formulas above, we can see that:

[0122] When Mi = 0, Ma = 0, and when (Mz - Ma) / ia < Md, the tendency of rotational direction will not be transmitted to the torsion bar spring. At this time, the torsion bar spring will not undergo torsional deformation and will not provide assistance. The reverse torque is entirely overcome by the steering gear structure. At the same time, since there is no torque feedback on the input shaft, the driver cannot obtain the road feel of steering through the steering wheel. When Md is relatively large, it plays a cut-off role for the direction torque Mz. The steering gear cannot provide assistance in a timely manner. After the reverse torque overcomes Md and causes the angular transmission system to rotate, the static friction becomes dynamic friction, and the internal resistance torque Md rapidly decreases, resulting in the rapid transmission of the reverse torque to the torsion bar and the input shaft, and the angle θ rapidly increases. After the motor responds, it outputs an assistance torque, and the resistance torque on the input shaft rapidly decreases again. The torque feedback fluctuates greatly, and the impact on the structure is relatively large, and the steering stability is poor.

[0123] When Mi ≠ 0, Ma ≠ 0, Md will increase the requirement for the steering input torque and increase the minimum response value of assistance, thus making the steering feel heavy. The existence of Md is equivalent to introducing a relatively large cut-off band in the angular transmission system. The fluctuation of the steering feedback torque cannot be fully fed back to the angle sensor, and the steering gear cannot provide the assistance torque in a timely manner. Also, because each torque has a direction, when Md is relatively large, the damping effect it introduces to the system is relatively large. The steering hand torque changes direction, and the system response has an obvious delay. The response duration and response accuracy are both poor, and it is difficult to meet the requirements for steering control stability.

[0124] In view of the above technical status, the prior art has the following defects:

[0125] 1. The worm and gear reduction mechanism in the angular deceleration system causes relatively serious shortcomings in the reverse force feedback performance of the entire steering gear, thus seriously affecting the performance of the product.

[0126] The reduction ratio ia of the angular deceleration system is generally 22 - 26. The two magnetic rings of the angle sensor are respectively fixed on two parts, the worm and the steering input shaft. These two components are connected by a torsion bar spring. The magnitude of their relative rotation amount is linearly related to the magnitude of the steering resistance torque. The larger the rotation angle, the larger the output current of the angle sensor, and the assistance motor will also provide a larger assistance torque, so as to provide sufficient output torque for steering.

[0127] Using the worm and gear reduction mechanism as the first-stage reduction mechanism of the steering hand torque will make the aforementioned Md relatively large, resulting in worse torque feedback, road feel feedback, assistance response accuracy, and response randomness.

[0128] The specific reasons are as follows:

[0129] 1) Worm gear reducers are inefficient. Even without self-locking, the resistance torque during reverse rotation (i.e., the worm gear driving the worm) is still large, an order of magnitude greater than that of conventional spur gears and helical gears. (Note: The resistance torque differs between worm-driven worm gear rotation and worm-driven worm gear rotation; the latter is much larger, causing a significant change in Md during active steering and reverse steering.) Multiplying this resistance torque by the reduction ratio ia of the angular reduction system gives the actual resistance torque in the angular reduction system. This resistance torque is tens of times larger than that of spur gear and helical gear reducers. This resistance torque acts as a damping filter in the steering resistance torque feedback process of the output shaft, preventing all steering feedback resistance fluctuations from being transmitted to the steering wheel. Only the large torque portion is transmitted, causing subtle road feel fluctuations to go undetected by the steering wheel. The fluctuating resistance torque changes drastically, creating a jarring sensation and resulting in very poor road feel feedback. The aforementioned problems caused by the large Md become significantly exacerbated.

[0130] 2) The inability to smoothly transmit the resistance torque to the input shaft results in the input shaft and worm gear failing to accurately follow changes in the steering feedback resistance torque. Consequently, the controller cannot provide a high-precision relative angle signal, leading to poor power assist responsiveness. When the steering resistance torque overcomes the system's internal resistance torque and is transmitted to the worm gear, and then through the torsion bar spring to the input shaft, the steering resistance torque is already very large, exceeding the level that should provide steering assistance. This causes the power assist motor to fail to provide resistance torque in time. As the worm gear begins to rotate relative to the input shaft after overcoming static friction, the resistance torque in the manual input reduction system drops rapidly. This easily leads to the steering resistance being quickly transmitted to the input shaft through the torsion bar, causing the input shaft and worm gear to rotate rapidly relative to each other, creating a turning impact. The power assist motor also quickly provides a large assist torque, resulting in a torque impact within the steering gear. This significantly affects the structural strength of the steering gear, reducing its lifespan and also resulting in poor steering operation stability.

[0131] 2. The worm gear is an eccentric semi-circular wheel with a large structural size, which results in a large moment of inertia when rotating around the steering gear main shaft. During frequent steering and reversing, the impact on the worm is relatively large under the same angular acceleration. At the same time, the worm gear is located before the fourth stage of reduction, and its rotational speed is still relatively high. In addition, it has a large mass and a large eccentricity, which generates a large centrifugal force on the steering gear, resulting in more obvious vibration.

[0132] 3. The steering gear housing is a deep, bowl-shaped structure. All stages of the reduction gear system are installed within this housing. The installation depth is significant, making installation difficult and requiring high precision control. High precision machining of the housing is essential. For example, the third and fourth stage fixed gears and their corresponding positioning components use external cylindrical surfaces for positioning. The mating surfaces on the housing require machining cylindrical surfaces. However, achieving the required precision for such large cylindrical surfaces is extremely challenging, resulting in high machining costs during mass production. The worm gear's installation space on the housing is within a semi-enclosed cavity, increasing the difficulty of installation due to the lack of visibility, alignment, checking the fit, and adjustments.

[0133] 4. Due to the series and stacked assembly of the various reduction modules, the main support consists of only two bearings on both sides. There is no housing structure between the first and fourth stages as a support and positioning component. Furthermore, the axial span of the main reduction mechanism is relatively large. Under the radial force, the main shaft (virtual shaft) will bend, easily deteriorating or even failing to guarantee the fit accuracy of the components at each stage. This leads to increased imperfections in gear meshing, a gradual deterioration in the uniformity of axial load distribution, and accelerated wear. Without adding a support structure in the intermediate stage, the dimensions of the connecting structures between the serial ports of each stage must be increased to ensure connection strength, obviously increasing the structural size and overall weight, thus increasing costs. Simultaneously, due to the stacked installation of each stage, the fit error will accumulate at each stage, resulting in a large total error. To control the total error, the fit accuracy of each stage needs to be increased, increasing processing difficulty and cost. Furthermore, the lack of intermediate-stage radial support from the housing results in low radial positioning accuracy for the third and fourth stage gears, making it difficult to guarantee meshing accuracy. Because the third and fourth stages transmit large torques, the uniformity of gear load distribution under radial force is also not ideal, leading to faster wear and increased noise and abnormal sounds.

[0134] 5. The transmission system has multiple stages, including four stages, with the first and second stages being spur gear transmissions. This results in a large accumulation of transmission errors in the entire main reduction system, which is detrimental to the control of steering accuracy.

[0135] 6. The four-stage reduction gear results in a large axial dimension, and the motor is located on the rear side of the steering gear main shaft, making the overall axial dimension of the steering gear very large. When arranging the steering gear in the vehicle, the requirements for the axial dimension of the main shaft are quite stringent, while the requirements for the radial dimension are less stringent. Under the current technological framework, the rear-mounted motor mechanism makes it impossible to install the steering gear on the vehicle.

[0136] 7. The input and output shafts intersect at a cross shape, resulting in a relatively large eccentricity determined by the meshing center distance of the worm gear. This value strongly influences the worm gear transmission ratio and transmission strength and cannot be arbitrarily changed. This leads to two disadvantages: 1) The large and fixed eccentricity is not conducive to the connection and arrangement of upstream and downstream components of the steering system, resulting in inflexible application; 2) The large eccentricity causes a significant increase in the radial dimension of the steering gear in the driving direction, which is also detrimental to the placement of the steering gear on the vehicle, while also increasing the weight of the housing and raising costs.

[0137] 8. The main housing structure is very large and a single structure, necessitating the use of a single material for processing. Due to the significant difference in size between the steering gear and the internal components in the opposite directions near the output shaft and near the motor, the internal stress level in the rear part of the housing (motor side) is very low, resulting in very low material utilization. (Improving material utilization requires reducing wall thickness; however, if the wall thickness is less than a certain value, processing becomes impossible, leading to a high scrap rate). Therefore, using a one-piece housing results in a very heavy overall housing, low overall material utilization, wasted resources, and increased processing difficulty and cost.

[0138] To at least partially solve the above problems, this application discloses a deceleration device, a power steering system, and a vehicle.

[0139] Exemplary embodiments according to this application will now be described in more detail with reference to the accompanying drawings.

[0140] As shown in Figures 2, 3, and 4, in some embodiments, the reduction device 3 includes a multi-stage transmission mechanism, which can be a three-stage transmission mechanism 10. The three-stage transmission mechanism 10 may include a first-stage transmission mechanism 200, a second-stage transmission mechanism 300, and a third-stage transmission mechanism 400. The first-stage transmission mechanism 200, the second-stage transmission mechanism 300, and the third-stage transmission mechanism 400 sequentially transmit power and perform deceleration and torque amplification.

[0141] In some embodiments, the first-stage transmission mechanism 200 can be a gear set structure, the second-stage transmission mechanism 300 can be a planetary gear set structure, and the third-stage transmission mechanism 400 can be a planetary gear set structure. Since the planetary gear set structure has a large transmission ratio, by making the second-stage transmission mechanism 300 and the third-stage transmission mechanism 400 of the three-stage transmission mechanism 10 of the reduction device 3 planetary gear set structures with large transmission ratios, the reduction device 3 can achieve a better reduction and torque amplification effect while having fewer reduction stages. This is beneficial for improving the response speed of the reduction device 3, thereby reducing the steering error of the power steering system 2 and the vehicle 1.

[0142] In some embodiments, the speed reduction device 3 may further include a first housing 101 and a second housing 102; a portion of the transmission mechanism is provided in the first housing 101, which may be a single-stage transmission mechanism;

[0143] The second housing 102 is provided with another part of the transmission mechanism, which can be a two-stage transmission mechanism;

[0144] The first housing 101 and the second housing 102 are detachably connected, and the multi-stage transmission mechanism is detachably connected.

[0145] During the processing and assembly of the speed reduction device 3, the first housing 101 and the second housing 102 can be in a separate state. After the speed reduction device 3 is assembled, the first housing 101 and the second housing 102 are in a relatively fixed connection state.

[0146] As shown in Figures 1 and 2, a mounting hole 115 is provided on one side of the first housing 101 for fixing the first housing 101 to other components. An output shaft sealing ring 108 is also provided on one side of the first housing 101 for sealing the output shaft. As shown in Figure 4, the second housing 102 is connected to the first housing 101 by a first connecting bolt 114. A gasket 113 is also provided between the first connecting bolt 114 and the first housing 101.

[0147] In this embodiment, the speed reduction device 3 adopts a split housing structure, in which the multi-stage transmission mechanism is set in different housings, which facilitates the disassembly and maintenance of the multi-stage transmission mechanism, thereby reducing the machining accuracy and assembly difficulty of the speed reduction device 3.

[0148] In some embodiments, the first housing 101 may be provided with a third-stage transmission mechanism 400 of the three-stage transmission mechanism 10; the second housing 102 may be provided with a first-stage transmission mechanism 200 and a second-stage transmission mechanism 300 of the three-stage transmission mechanism 10, and the input end of the third-stage transmission mechanism 400 and the output end of the second-stage transmission mechanism 300 may be detachably connected.

[0149] Therefore, the first housing 101 and the third-stage transmission mechanism 400 can be integrated as a whole (e.g., the front deceleration part 700), and the second housing 102, the first-stage transmission mechanism 200, and the second-stage transmission mechanism 300 can be integrated as another whole (e.g., the rear deceleration part 800). These two wholes can be detachably connected, which makes the disassembly and maintenance of the deceleration device 3 more convenient, helps to reduce the maintenance cost of the deceleration device 3, and improves the maintenance efficiency of the deceleration device 3.

[0150] In one embodiment, as shown in FIG5, the deceleration device 3 can be divided into two subsystems: a front deceleration section 700 and a rear deceleration section 800. Dividing it into two subsystems has the following advantages:

[0151] 1. The 800 RPM at the rear of the decelerator can be switched to a dual-motor input version;

[0152] 2. Different versions of the 600 spatial position S and H of the steering input mechanism can be switched;

[0153] 3. The rear 800 section of the deceleration unit can be switched to change the power input and transmission ratio, while keeping the front 700 section of the deceleration unit shared.

[0154] 4. The second housing 102 can be switched to adjust the spatial position of the motor to meet installation requirements while keeping the other components unchanged, thereby minimizing the amount of modification.

[0155] 5. The state of the first housing 101 can be switched to change the position of the mounting holes as needed.

[0156] 6. The first housing 101 and the output shaft 416 can be switched to change the required extension length of the output shaft 416.

[0157] 7. The version status of the front 700 deceleration section can be switched while keeping the status of the rear 800 deceleration section unchanged. For example, the output direction of the output shaft 416 can be changed to form a 90° angle with the main shaft of the rear 800 deceleration section.

[0158] 8. The third-stage transmission mechanism 400 has a large load and wears faster than the first two stages, making it more likely to be damaged. The third-stage transmission mechanism 400 can be removed separately. If after-sales replacement of parts on the third stage is required, only the front part of the reduction gear 700 needs to be removed. No other system needs to be touched, making disassembly and assembly convenient.

[0159] 9. With a reduced machining depth for the housing, the machining difficulty is lower while maintaining the same precision requirements. This also ensures higher installation accuracy and reduces installation difficulty.

[0160] 10. The first housing 101 is more susceptible to damage than the others. If it is damaged, only the first housing 101 can be replaced, thus reducing maintenance costs.

[0161] In one embodiment, as shown in Figures 3 and 4, the multi-stage transmission mechanism includes:

[0162] The first-stage transmission mechanism 200 (first-stage reduction mechanism) has an input end for connection to the drive motor.

[0163] The second-stage transmission mechanism 300 (second-stage reduction mechanism) has its input end connected to the output end of the first-stage transmission mechanism 200.

[0164] Therefore, the power output by the drive motor 501 can be transmitted to the second-stage transmission mechanism 300 through the first-stage transmission mechanism 200, and the first-stage transmission mechanism 200 and the second-stage transmission mechanism 300 can reduce speed and increase torque.

[0165] The first-stage transmission mechanism 200 and the second-stage transmission mechanism 300 are arranged in combination within the second housing 102. Specifically, the first-stage transmission mechanism 200 and the second-stage transmission mechanism 300 are interconnected and jointly supported within the second housing 102.

[0166] In one embodiment, as shown in Figures 6, 7, and 8, the first-stage transmission mechanism 200 includes at least:

[0167] 220 primary output wheel;

[0168] The first-stage output wheel 220 is used to connect to the drive motor 501. The first-stage output wheel 220 is also used to connect to the input end of the second-stage transmission mechanism 300, so that the power output by the drive motor 501 can be transmitted to the second-stage transmission mechanism 300 through the first-stage output wheel 220 of the first-stage transmission mechanism 200.

[0169] The first-stage transmission mechanism 200 may further include a first-stage key connection mechanism 211, which is located at the middle of the first-stage output wheel 220 and is used to connect the first-stage output wheel 220 and the second-stage transmission mechanism 300. Connecting the first-stage output wheel 220 and the second-stage transmission mechanism 300 via the first-stage key connection mechanism 211 makes the connection between the first-stage output wheel 220 and the second-stage transmission mechanism 300 more stable.

[0170] The first-stage transmission mechanism 200 can be a helical gear set. This stage of the reduction mechanism is used to transmit the power of the power-assist motor to the main shaft of the reduction device 3. The motor shaft and the main shaft of the reduction device 3 are not coaxial and can be arranged in parallel. The motor is located on one side of the reduction device 3, and there is a center distance L between the two shafts.

[0171] In one embodiment, the first-stage output wheel 220 is a first-stage output gear or a first-stage output worm gear, and the transmission teeth 318 of the first-stage output gear are spur teeth or helical teeth.

[0172] In some embodiments, the first-stage transmission mechanism 200 and the second-stage transmission mechanism 300 are connected in series via a secondary connecting spline inner spline 232 and a secondary connecting spline outer spline 332.

[0173] In one embodiment, as shown in Figures 3 and 4, the multi-stage transmission mechanism includes:

[0174] The third-stage transmission mechanism 400 (third-stage reduction mechanism) has its input end connected to the output end of the second-stage transmission mechanism 300. The third-stage transmission mechanism 400 is housed within the first housing 101. The input end of the third-stage transmission mechanism 400 is detachably connected to the output end of the second-stage transmission mechanism 300.

[0175] In one embodiment, the second-stage transmission mechanism 300 includes:

[0176] The secondary sun gear 303 is connected to the first-stage transmission mechanism 200 so that the first-stage transmission mechanism 200 drives the secondary sun gear 303 to rotate.

[0177] Multiple planetary gear assemblies 319 are distributed sequentially along the circumference of the secondary sun gear 303 and mesh with the secondary sun gear 303 respectively;

[0178] The secondary internal gear ring 306, and multiple planetary gear assemblies 319 are at least partially located in the secondary internal gear ring 306 and respectively mesh with the secondary internal gear ring 306.

[0179] This allows the second-stage transmission mechanism 300 to have a higher transmission ratio and a higher speed reduction and torque increase effect.

[0180] The planetary gear assembly 319 may include a rear planetary gear 304 and a front planetary gear 305. The rear planetary gear 304 is located near the first-stage transmission mechanism 200 and meshes with the second-stage sun gear 303, so that the planetary gear assembly 319 meshes with the second-stage sun gear 303. The front planetary gear 305 is located near the third-stage transmission mechanism 400 and is coaxially fixed with the corresponding rear planetary gear 304. The second-stage internal gear ring 306 is fixedly connected to the second housing 102, and the front planetary gear 305 is disposed in the second-stage internal gear ring 306 and meshes with the second-stage internal gear ring 306, so that the planetary gear assembly 319 meshes with the second-stage internal gear ring 306.

[0181] In one embodiment, as shown in Figures 6 and 7, the second-stage transmission mechanism 300 includes:

[0182] The secondary sun gear 303 is connected to the primary key connection mechanism 211 and can be driven by the primary output wheel 220. That is, the primary output wheel 220 can drive the secondary sun gear 303 to rotate through the primary key connection mechanism 211.

[0183] Multiple planetary gear rear wheels 304 are positioned close to the first-stage transmission mechanism 200, and the planetary gear rear wheels 304 mesh with the second-stage sun gear 303;

[0184] Multiple planetary gear front wheels 305 are arranged close to the third-stage transmission mechanism 400, and the planetary gear front wheels 305 and the corresponding planetary gear rear wheels 304 are coaxially fixed relative to each other.

[0185] The secondary internal gear ring 306 is fixedly connected to the second housing 102. The planetary gear front wheel 305 is disposed in the secondary internal gear ring 306 and meshes with the secondary internal gear ring 306.

[0186] Therefore, the second-stage sun gear 303, multiple planetary rear gears 304, and multiple planetary front gears 305 of the second-stage transmission mechanism 300 can be combined to form a double planetary gear set structure, which can make the transmission ratio of the second-stage transmission mechanism 300 higher and the speed reduction and torque increase effect better.

[0187] In one embodiment, as shown in Figures 9 and 10, the rear planetary gear 304 is provided with a connecting groove 341, and the front planetary gear 305 is provided with a connecting shaft 351. The connecting shaft 351 is inserted into the connecting groove 341, so that the front planetary gear 305 and the corresponding rear planetary gear 304 are coaxially fixed. This allows the rear planetary gear 304 and the front planetary gear 305 to be as close as possible, which helps to reduce the axial dimension of the second-stage transmission mechanism 300 and makes the overall size of the reduction device 3 smaller.

[0188] In one embodiment, as shown in Figures 7 and 9, the second-stage transmission mechanism 300 further includes:

[0189] The secondary rear support 307 is located between the primary output wheel 220 and the planetary rear wheel 304.

[0190] The secondary front support 308 is located between the planetary gear front wheel 305 and the third-stage transmission mechanism 400. The secondary front support 308 is connected to the secondary rear support 307, thereby stably supporting the planetary gear rear wheel 304 and the planetary gear front wheel 305, making the operation of the second-stage transmission mechanism 300 more stable.

[0191] Specifically, the second-stage transmission mechanism has over 300 secondary support connecting bolts 311. These bolts pass through the rear planetary gear 304 and the front planetary gear 305, and the secondary rear support 307 and the secondary front support 308 are connected via these bolts. This ensures a more stable connection between the secondary front support 308 and the secondary rear support 307.

[0192] In one embodiment, as shown in Figures 6 and 7, a secondary support radial bearing 301 and a secondary support axial bearing 302 are provided between the primary output wheel 220 and the secondary rear support 307, allowing the primary output wheel 220 to support the rotation of the secondary rear support 307. The secondary support radial bearing 301 and the secondary support axial bearing 302 reduce the friction between the primary output wheel 220 and the secondary rear support 307, making their relative rotation smoother, reducing wear between them, and improving the transmission efficiency and service life of the reduction gear 3.

[0193] In one embodiment, as shown in Figures 6 and 7, a secondary sun gear bearing 316 is provided between the secondary sun gear 303 and the secondary front support 308, and the secondary front support 308 supports the rotation of the secondary sun gear 303. This reduces the friction between the secondary sun gear 303 and the secondary front support 308, resulting in less wear and thus higher transmission efficiency and service life of the reduction gear 3.

[0194] During installation, an axial clamping force exists between the third housing 103 and the main support 105, pressing the primary output wheel main bearing 208, the secondary support main bearing 310, and the secondary sun gear bearing 316 together to ensure the rigidity requirements for use. The primary output wheel 220, the secondary sun gear 303, and the secondary front support 308 are press-fitted between the aforementioned three bearings. This structure is convenient to install, has high axial and radial positioning accuracy for each component, high support strength, and is not prone to noise. Specifically, the outer ring 233 of the primary main bearing 208 is connected to the primary output gearbox base 204, and the inner ring of the primary main bearing 208 is connected to the third housing 103.

[0195] In some embodiments, the secondary front bracket 308 can be detachably connected to the input end of the third-stage transmission mechanism 400, making it more convenient to detachably connect the input end of the third-stage transmission mechanism 400 and the output end of the second-stage transmission mechanism 300.

[0196] In one embodiment, as shown in Figures 6 and 7, the secondary front support 308 includes:

[0197] A secondary key connection mechanism 317 is located in the middle of the secondary front bracket 308 and is used to connect the secondary transmission mechanism 400, allowing the secondary front bracket 308 to be detachably connected to the input end of the third-stage transmission mechanism 400. This enables the secondary front bracket 308 to be easily and detachably connected to the input end of the third-stage transmission mechanism 400, and when connected, the secondary front bracket 308 can stably transmit power to the input end of the third-stage transmission mechanism 400.

[0198] In some embodiments, the secondary front support 308 includes:

[0199] The transmission gear 318 is located on the side of the secondary front support 308 facing the third-stage transmission mechanism 400. The transmission gear 318 is a hyperbolic helical gear or a spur gear. Thus, the secondary front support 308 can be easily connected to the steering input mechanism 600 via the transmission gear 318.

[0200] In one embodiment, as shown in Figures 6, 11, and 12, the speed reduction device 3 further includes:

[0201] The steering input mechanism 600 (angular reduction mechanism) is used to connect externally to the steering device and internally to the secondary front support 308, driving the secondary front support 308 to rotate, so as to transmit the power input by the steering hand force to the secondary front support 308. The steering input mechanism 600 can mesh with the transmission gear 318 of the secondary front support 308, thereby connecting the steering input mechanism 600 to the secondary front support 308.

[0202] Specifically, the axial direction of the steering input mechanism 600 can be made perpendicular to the axial direction of the secondary front support 308, so that the shape of the deceleration device 3 is more compatible with the structure of the vehicle 1.

[0203] In one embodiment, as shown in Figures 11 and 12, the steering input mechanism 600 includes:

[0204] Input shaft 603 is used to connect to the steering device externally.

[0205] Torque bar 608, the first end of which is connected to input shaft 603 via input shaft pin 601;

[0206] Input gear 609 is used to connect to secondary front bracket 308, and the second end of torsion bar 608 is connected to input gear 609;

[0207] Angle sensor 605 is sleeved on the outside of input shaft 603 and is used to detect the relative rotation angle between input shaft 603 and input gear 609.

[0208] Thus, the input shaft 603 of the steering input mechanism 600 can transmit manual force to the input gear 609 through the torsion bar 608, and the rotation angle of the input shaft 603 can be detected by the angle sensor 605, so as to control the torque output by the drive motor 501.

[0209] The input shaft 603 can be a hollow shaft, with a torsion bar 608 disposed inside it. The first end of the torsion bar 608 is connected to the input shaft 603 via an input shaft pin 601, thus ensuring a more stable connection between the torsion bar 608 and the input shaft 603. The input shaft 603 is rotatably connected to the fourth housing 104 via an input shaft main bearing 604. The input gear 609 is supported by an input gear main bearing 607 and an input gear secondary bearing 610. The input gear main bearing 607 provides upper radial and axial support, while the input gear secondary bearing 610 provides lower radial support. An input gear washer 611 is disposed in the shaft hole of the main bracket 105, with its upper end face engaging with the shaft end face of the input gear 609 and its lower end face engaging with the lower surface of the bearing seat on the main bracket 105, serving as a downward axial limit for the input gear 609.

[0210] In some embodiments, the centerline of the steering input mechanism 600 intersects or staggers the main shaft axis of the reduction gear 3 at a 90° angle. The center distance S between the two shafts is a variable, and its size can be adjusted as needed during the design phase by changing the helix angle of the input gear 609 and the secondary front support 308. Without changing the existing component dimensions, changing the value of S will cause a corresponding change in the value of H. This change in H can be maintained by adjusting the dimensions of the input shaft 603 and the input gear 609.

[0211] A torsion bar sealing ring 602 is provided at the upper end of the torsion bar 608 to prevent contaminants from entering the system through the mating surface between the torsion bar 608 and the inner hole of the input shaft 603. A torsion bar bushing 606 is provided at the lower end of the torsion bar 608 to support the lower end of the torsion bar 608 and keep the torsion bar 608 coaxial with the input gear 609.

[0212] An input shaft sealing ring 110 is provided at the upper end of the input shaft 603. Its outer circular surface is pressed onto the mounting hole of the fourth housing 104 and mates with the shaft surface of the input shaft 603 to prevent contaminants from entering the system.

[0213] An angle sensor 605 is housed within the cavity enclosed by the second housing 102 and the fourth housing 104. Its main body is clamped onto the second housing 102, and its upper and lower magnetic rings are respectively welded to the input shaft 603 and the input gear 609. When the two rotate relative to each other, the angle sensor can detect this angle value and transmit the signal to the controller. A sealing gasket 106 is provided between the second housing 102 and the fourth housing 104 for sealing.

[0214] In one embodiment, as shown in Figures 6, 11, and 12, the speed reduction device 3 further includes:

[0215] The main support 105 is disposed between the second-stage transmission mechanism 300 and the third-stage transmission mechanism 400. The main support 105 is fixedly connected to the second housing 102 to improve the structural strength of the second housing 102.

[0216] The input gear 609 of the steering input mechanism 600 meshes with the secondary front bracket 308, and the axial end of the input gear 609 is connected to the main bracket 105, thereby making the installation of the input gear 609 more stable.

[0217] In one embodiment, as shown in Figures 6, 7, and 13, the third-stage transmission mechanism 400 includes:

[0218] The third-stage sun gear 403 is detachably connected to the second-stage front bracket 308, and the third-stage sun gear 403 can be driven by the second-stage front bracket 308.

[0219] Multiple third-stage planetary gears 402, which mesh with a third-stage sun gear 403;

[0220] The third-stage internal gear ring 401 is fixedly connected to the first housing 101, and the third-stage planetary gear 402 is disposed in the third-stage internal gear ring 401 and meshes with the third-stage internal gear ring 401.

[0221] The third-stage transmission mechanism 400 forms a planetary gear structure by combining a third-stage sun gear 403, multiple third-stage planetary gears 402, and a third-stage internal gear ring 401. This allows the third-stage transmission mechanism 400 to have a high transmission ratio while maintaining a small size.

[0222] Specifically, the third-stage sun gear 403 can be connected to the second-stage key connection mechanism 317 of the second-stage front bracket 308, allowing for a detachable connection between the third-stage sun gear 403 and the second-stage front bracket 308. This makes connecting and separating the third-stage sun gear 403 and the second-stage front bracket 308 more convenient, and when the third-stage sun gear 403 is connected to the second-stage front bracket 308, the second-stage front bracket 308 can stably transmit power to the third-stage sun gear 403.

[0223] In one embodiment, as shown in Figures 6 and 7, a secondary support main bearing 310 is provided between the secondary front support 308 and the main support 105.

[0224] A main bearing 409 for the third-stage sun gear is provided between the main support 105 and the third-stage sun gear 403, and the main support 105 supports the rotation of the third-stage sun gear 403.

[0225] The three-stage sun gear main bearing 409 can reduce the friction between the main support 105 and the three-stage sun gear 403, allowing the three-stage sun gear 403 to rotate more smoothly relative to the main support 105, which is beneficial to improving the transmission efficiency and service life of the speed reduction device 3.

[0226] The secondary support main bearing 310 includes an inner ring 333 and an outer ring 334.

[0227] In one embodiment, as shown in Figures 6, 7, and 13, the third-stage transmission mechanism 400 further includes:

[0228] The third-stage rear support 404 is located between the second-stage transmission mechanism 300 and the third-stage planetary gear 402.

[0229] The third-stage front bracket 405 is located at the output end of the third-stage transmission mechanism 400, and the third-stage front bracket 405 is fixedly connected to the third-stage rear bracket 404.

[0230] The output shaft 416 is connected to the three-stage front bracket 405 and can be driven to rotate by the three-stage front bracket 405.

[0231] The third-stage planetary gear 402 is supported by the third-stage rear bracket 404 and the third-stage front bracket 405, which makes the operation of the third-stage transmission mechanism 400 more stable.

[0232] In one embodiment, as shown in Figures 6, 7, and 13, the third-stage transmission mechanism 400 further includes:

[0233] The third-stage planetary bearing 407 is disposed in the third-stage planetary gear 402;

[0234] The third-stage planetary shaft 406 is disposed in the third-stage planetary bearing 407 and supports the rotation of the third-stage planetary bearing 407.

[0235] The third-stage planetary gear 402 is supported by the third-stage planetary shaft 406 and the third-stage planetary bearing 407, which makes the rotation of the third-stage planetary gear 402 smoother and reduces the frictional resistance.

[0236] Specifically, the first end of the third-stage planetary shaft 406 can be connected to the third-stage rear support 404, and the second end of the third-stage planetary shaft 406 can be connected to the third-stage front support 405, so that the third-stage front support 405 and the third-stage rear support 404 are relatively fixedly connected, which enables the third-stage planetary shaft 406 to support the third-stage planetary gear 402 more stably, and enables the third-stage planetary gear 402 to operate more stably.

[0237] Specifically, the first end of the third-stage planetary shaft 406 can be connected to the third-stage rear support 404 by screws, and the second end of the third-stage planetary shaft 406 can be connected to the third-stage front support 405 by screws 415, thus fixing the third-stage front support 405 and the third-stage rear support 404 relatively and securely. This makes the connection between the two ends of the third-stage planetary shaft 406 and the third-stage rear support 404 more stable and convenient, improving the assembly efficiency of the reduction gear 3. The third-stage planetary shaft 406 has threaded holes on both sides, and is connected and pressed onto the left and right supports by two pairs of third-stage planetary shaft pressure plates 413 and countersunk screws 412, thereby enhancing the connection strength between the third-stage rear support 404 and the third-stage front support 405. The third-stage rear support 404 is also supported on the flange cylindrical surface 131 of the main support 105 by a bearing 408, providing radial support for the rear support.

[0238] In one embodiment, as shown in Figures 6, 7, and 13, a third-stage rear support main bearing 408 is provided between the main support 105 and the third-stage rear support 404.

[0239] An output shaft auxiliary bearing 410 is provided between the third-stage sun gear 403 and the third-stage front support 405;

[0240] An output shaft main bearing 411 is provided between the third-stage front bracket 405 and the first housing 101.

[0241] This allows for smoother relative rotation between the main support 105 and the third-stage rear support 404, between the third-stage sun gear 403 and the third-stage front support 405, and between the third-stage front support 405 and the first housing 101.

[0242] In some embodiments, the three-stage internal gear ring 401 and the first housing 101 can be integrated into one structure, thereby improving the structural strength of the three-stage internal gear ring 401 and reducing the number of parts in the speed reduction device 3.

[0243] In one embodiment, as shown in Figures 3, 4, 5, and 7, the speed reduction device 3 further includes:

[0244] The third housing 103 is detachably connected to the second housing 102. The first-stage output wheel 220 is supported and rotated by the third housing 103 to make the rotation of the first-stage output wheel 220 more stable.

[0245] The first housing 101, the second housing 102, and the third housing 103 constitute the steering housing assembly 100, which forms the peripheral structure of the power steering 2 and is used for the installation, protection, sealing of the internal subsystems, installation of accessories thereon, and installation and connection of the power steering 2.

[0246] The third housing 103 is connected to the second housing 102 by the second connecting bolt 112, and a connecting washer 113 is provided between the third housing 103 and the nut of the second connecting bolt 112.

[0247] In one embodiment, as shown in Figures 6, 7, and 8, the first-stage output wheel 220 includes:

[0248] The first-stage output gear ring 203 is used to connect the motor control mechanism 500.

[0249] The first-stage output gearbox base 204 is fixedly connected to the first-stage output gear ring 203. The first-stage output gearbox base 204 is used to connect the third housing 103 and the second-stage sun gear 303 respectively.

[0250] The primary output gear housing 204 is made of a low-density alloy material, such as aluminum alloy, to reduce the overall weight of the output gear and decrease its moment of inertia. The primary output gear ring 203 is made of high-strength alloy steel to meet the strength requirements of the gear teeth. This combination design reduces the weight by approximately 47.6% and the moment of inertia by approximately 41.4% compared to gears made of a single material.

[0251] Since the primary output gear base 204 is made of aluminum alloy or other low-density metal alloy, the first support surface 230 and the second support surface 231 of the secondary support on it need to be specially treated to improve surface hardness and wear resistance, such as surface heat treatment, cold work hardening, surface anodizing, surface electroplating, and adding alloy materials.

[0252] The primary key connection mechanism 211 can be positioned in the middle of the primary output gearbox base 204, thereby positioning the primary output wheel 220 in the middle. By connecting the primary output gearbox base 204 and the second-stage transmission mechanism 300 through the primary key connection mechanism 211, the primary output wheel 220 can be connected to the second-stage transmission mechanism 300.

[0253] In one embodiment, as shown in Figures 6, 7, and 8, a primary output wheel main bearing 208 is provided between the third housing 103 and the primary output gearbox base 204, and the third housing 103 supports the rotation of the primary output wheel 220. This allows for smoother relative rotation between the third housing 103 and the primary output gearbox base 204.

[0254] In one embodiment, the first housing 101 is made of die-cast iron or other high-strength alloy material, primarily for providing high-strength mounting connections and support for the output shaft main bearing.

[0255] The main support 105 is made of high-strength alloy materials, such as chromium-manganese alloy and high-carbon steel, to provide sufficient structural strength for the bearings and components mounted on it. At the same time, the bearing housing 335 of this part is also directly used on the inner ring surface of the main bearing 408 of the third-stage rear support.

[0256] The second shell 102, third shell 103, and fourth shell 104 are all made of low-density die-cast alloy material, such as cast aluminum, to reduce the weight of these three shells. Reason: The wall thickness of the die-cast shell cannot be too thin, for example, not less than 3mm, but a thickness of 3mm can easily lead to excessively low modal frequencies in the shell structure, easily generating resonance noise. If the same high-strength alloy material as the first shell 101 is used, even with the minimum wall thickness, the maximum structural stress level on the second shell 102, third shell 103, and fourth shell 104 is relatively small, seriously wasting material properties. Therefore, using a low-density, low-strength material can meet the minimum wall thickness requirement, reduce the shell weight, and improve the utilization rate of material properties. In this embodiment, only the second shell 102, third shell 103, and fourth shell 104 are made of aluminum alloy, reducing the weight by 38.7% compared to a shell made solely of iron.

[0257] In some embodiments, the first-stage transmission mechanism 200 may include a first-stage idler gear 202 and a first-stage input gear 201. The first-stage idler gear 202 meshes with the first-stage output gear ring 203, and the first-stage input gear 201 meshes with the first-stage idler gear 202. The first-stage input gear 201 is used to connect the motor control mechanism 500. Through the first-stage input gear 201 and the first-stage idler gear 202 and the first-stage output gear ring 203, the distance between the motor control mechanism 500 and the first-stage output gear ring 203 can be adjusted more flexibly.

[0258] The first-stage idler gear 202 is rotatably supported on the first-stage idler shaft 207 via the first-stage idler bearing 206. The first-stage input gear 201 is supported on the third housing 103 via the first-stage input gear bearing 205.

[0259] As shown in Figures 2, 3, and 7, an embodiment of this application also provides a power steering system 2, which includes the deceleration device 3 as described in any one of the embodiments of this application.

[0260] In one embodiment, as shown in Figures 2, 3, and 7, the power steering system 2 further includes:

[0261] The motor control mechanism 500 is connected to the first-stage transmission mechanism 200 of the reduction gear 3 and is used to drive the first-stage transmission mechanism 200 of the reduction gear 3 to rotate. The power output by the motor control mechanism 500 is transmitted to the reduction gear 3, and after being decelerated and increased in torque in sequence by the first-stage transmission mechanism 200, the second-stage transmission mechanism 300 and the third-stage transmission mechanism 400 of the reduction gear 3, it is output from the output end of the reduction gear 3.

[0262] In one embodiment, as shown in Figures 2, 3, and 7, the motor control mechanism 500 includes:

[0263] One or two drive motors 501, each drive motor 501 including a motor shaft 510, the motor shaft 510 being connected to the first-stage transmission mechanism 200;

[0264] The drive motor 501 is fixedly connected to the second housing 102 of the reduction gear 3. Because the drive motor 501 has a fast response speed and can output a large torque, driving the reduction gear 3 with the drive motor 501 can make the power steering 2 more precise and faster in response.

[0265] The drive motor 501 is connected to the second housing 102 via motor connecting bolts 507. A motor sealing ring 506 is provided between the drive motor 501 and the second housing 102 to achieve a seal. The first-stage input gear bearing 205 and the first-stage input gear pair bearing 502 are located at both ends of the first-stage input gear 201, jointly constraining the other degrees of freedom of the first-stage input gear 201 except for the axial rotational degree of freedom. The first-stage input gear bearing 205 is mounted and positioned on the bearing seat on the third housing 103, and the first-stage input gear pair bearing 502 is mounted and positioned on the bearing bracket 505 on the drive motor 501. The bearing bracket 505 is bolted to the drive motor 501.

[0266] In one embodiment, as shown in Figures 2, 3, 7, and 14, the motor control mechanism 500 further includes:

[0267] The inner ring 503 of the coupling is connected to the motor shaft 510 and the first-stage input gear 201 of the reduction gear 3 respectively.

[0268] Damping buffer pad 504 is disposed between the inner ring 503 of the coupling and the first-stage input gear 201.

[0269] The inner ring 503 of the coupling is press-fitted onto the motor shaft 510 via a spline. Six damping buffer pads 504 are circumferentially arranged on the inner ring 503 of the coupling and are inserted together into the groove on the first-stage input gear 201. The coupling transmits power and damps shocks and fluctuations by compressing the damping buffer pads 504 through circumferential rotation. The circumferential arrangement of the damping buffer pads 504 on the motor shaft 510 also reduces the axial connection size.

[0270] Figure 15 shows a dual-motor power steering system 2. The first-stage transmission mechanism 200 contains two input wheels and two idler wheels. Two motors drive the two input wheels respectively. In this architecture, the included angle φ between the two sets of input structures can be flexibly set to meet space requirements. In addition, one or both idler wheels can be omitted.

[0271] In some embodiments, the first-stage transmission mechanism 200 may include two first-stage idler gears 202 and two first-stage input gears 201. The two first-stage idler gears 202 respectively mesh with the first-stage output gear 220, and the two first-stage input gears 201 mesh with the two first-stage idler gears 202 in a one-to-one correspondence.

[0272] Therefore, it is possible to set two motor control mechanisms 500 connected to two first-stage input gears 201, so as to output a greater torque to the first-stage output gear 220, or to reduce the power requirement of the motor control mechanism 500 to reduce costs.

[0273] Specifically, the two first-stage input gears 201 can be used to connect the two motor control mechanisms 500 in a one-to-one correspondence, so as to output a greater torque to the first-stage output wheel 220, or the power requirements of the motor control mechanism 500 can be reduced.

[0274] Alternatively, the two primary input gears 201 can be used to connect to a single motor control mechanism 500. This arrangement reduces the strength requirements for each primary input gear 201.

[0275] Figure 16 shows a dual-motor power steering system 2. The structure of the first-stage transmission mechanism 200 remains unchanged. The difference is that the power steering motor is changed from one to two. The two motors drive the two input wheels respectively, and the two input wheels simultaneously drive the idler wheel. Compared with setting a high-power, high-torque single motor, this architecture can use a small-sized, low-power dual motor, which can reduce motor costs, increase motor control redundancy, and also reduce the size to a certain extent.

[0276] In some embodiments, the first-stage transmission mechanism 200 may include a first-stage idler gear 202 and two first-stage input gears 201, with each of the two first-stage input gears 201 meshing with a first-stage idler gear 202. This reduces the number of first-stage idler gears 202, resulting in a smaller size and lower cost for the first-stage transmission mechanism 200.

[0277] Figure 17 shows a power steering system 2 with a main shaft arrangement of a vertical reduction gear 3. The first-stage input gear 201 is a helical gear, eliminating the intermediate idler gear. The drive motor 501 is connected to the first-stage input gear via a coupling, and the first-stage input gear 201 directly drives the first-stage output gear 220. The angle φ between the motor shaft and the main shaft of the reduction gear 3 can also be adjusted by the helical gear inclination angle, without needing to be specifically set to 90°. Furthermore, the motor shaft does not need to be parallel to the horizontal plane; it can be set at any angle around the main shaft of the reduction gear 3 as needed.

[0278] In some embodiments, the first-stage transmission mechanism 200 may include a first-stage input gear 201 that meshes with a first-stage output gear 220. The first-stage input gear 201 is used to connect to the motor control mechanism 500. This further reduces the number of first-stage idler gears 202, making the first-stage transmission mechanism 200 smaller and less expensive.

[0279] Figure 18 shows an alternative steering input mechanism, namely helical gear transmission. In the steering input mechanism 600, the input gear 609 and the gear on the secondary front support 308 are switched from hyperbolic spiral disc gears to helical gears. That is, the transmission gear 318 on the secondary front support 308 is switched from a hyperbolic spiral disc gear to a helical gear, while other structural elements remain unchanged. Simultaneously, the included angle δ between the input shaft and the main shaft of the reduction gear 3 can be set to any value between 60° and 120° as needed, without needing to be specifically set to 90°. This is achieved by adjusting the inclination angle of the helical gear. It should be noted that after switching to helical gears, the center distance S between the input shaft and the output shaft returns to 0 and cannot be changed.

[0280] Figures 19 and 20 show an alternative primary transmission mechanism, employing a worm gear as the primary transmission mechanism 200. Specifically, the primary output wheel 220 of the primary transmission mechanism 200 is a worm gear. The motor is connected to the worm gear via a coupling, and the worm gear axis crosses the main shaft of the reduction gear 3. The worm gear drives the worm wheel to rotate, transmitting power to the secondary transmission mechanism 300. The worm gear can be a metal worm gear or a non-metallic worm gear to reduce noise.

[0281] Alternatively, the three-stage internal gear ring 401 and the first housing 101 can be designed as a single unit, making the two parts into one, thus eliminating the need for the first housing sealing gasket 106 between them.

[0282] Alternatively, the second or third stage transmission mechanism 10 can be replaced with other types of reduction mechanisms, such as harmonic reduction mechanisms, RV reduction mechanisms, or pinwheel reduction mechanisms.

[0283] Alternatively, the third-stage transmission mechanism 400 can be switched from a single planetary gear set to a double planetary gear set without changing other structures.

[0284] Alternatively, the front-to-back separation of the second shell 102 and the third shell 103 can be changed to a vertical separation, meaning the semi-enclosed cavity formed by the second shell 102 and the third shell 103 is composed of two shells connected together. Similarly, it can also be modified into a left-to-right separation.

[0285] Alternatively, the first-stage output wheel 220 can be redesigned from a separate unit back to a single unit without altering the form of other structural components.

[0286] Alternatively, the connection between the first, second, and third stage transmission mechanisms 10 can be changed from a spline connection to other forms of connection without altering the overall structural form.

[0287] Alternatively, the front and rear supports and the corresponding intermediate connecting columns in the second-stage or third-stage transmission mechanism 10 can be designed as a single integrated support, eliminating the intermediate bolt connection structure.

[0288] Alternatively, the rear support in the second or third stage transmission mechanism 10 can be directly eliminated, leaving only the front support. At the same time, the planetary shaft can be locked to the corresponding support at one end without changing the form of the rest of the reduction mechanism.

[0289] Alternatively, the front support and output shaft in the third-stage transmission mechanism 10 can be separated into two components without changing the overall structural form.

[0290] As shown in Figure 21, an embodiment of this application also provides a vehicle 1, including a power steering system 2 according to any one of the above embodiments.

[0291] Vehicle 1 can be a pure electric vehicle or a hybrid vehicle.

[0292] The deceleration device 3, power steering device 2, and vehicle 1 disclosed in this application have the following characteristics:

[0293] 1. The steering input mechanism is located inside the reduction gear 3. The steering input mechanism employs a hyperbolic helical gear set, thereby converting the axial torque and speed of the input shaft into torque and speed along the output shaft. The position of the input shaft relative to the main shaft of the reduction gear 3 (S and H in Figure 12) can be adjusted by regulating the helical angle of the hyperbolic helical gears (the teeth of the secondary front support 308 and the input gear 609) to better match the overall steering system layout. Specific differences from existing technologies are as follows:

[0294] 1.1 The steering input mechanism adopts a reduction structure with higher transmission efficiency, achieving a transmission efficiency of over 0.95, compared to the 0.7-0.8 transmission efficiency of worm gears. This significantly reduces the transmission resistance torque Md, especially the resistance torque of reverse transmission, thereby solving the problems of large fluctuations in steering feedback torque, obvious impact, power assist lag, insufficient power assist response accuracy, and limited power assist range caused by worm gears as input stage reduction mechanisms. This ensures sufficient steering operation stability and safety, and improves road feel feedback and steering smoothness.

[0295] 1.2 Shortening the center distance S between the input and output shafts makes the entire reduction gear 3 more compact, reducing weight and cost. The output wheel of the steering input mechanism (the teeth on the secondary front bracket 308) is a full-circumferential gear, eliminating the drawbacks of eccentricity, preventing centrifugal force and centrifugal vibration; the gear disk size is reduced, the moment of inertia is also smaller, and the inertial torque is smaller at the same angular velocity, contributing to improving the overall efficiency and response speed of the steering gear.

[0296] 1.3 The input shaft of the steering input mechanism is no longer arranged on one side of the steering gear, but is basically intersected with the main shaft of the reduction gear 3 and inserted directly into the interior of the reduction gear 3. The center distance S between the two shafts can be designed and shaped within ±40mm as needed, and zero eccentricity can be achieved.

[0297] 1.4 The driven gear is directly integrated with the secondary front bracket 308 as a single component. This is primarily because gears are simpler to machine than worm gears, allowing for integrated processing. Designing it as a single unit ensures both transmission and structural strength while reducing radial and axial dimensions, thus reducing weight and facilitating better structural layout, increasing space utilization, and improving compactness. Furthermore, the integrated design eliminates the need for connecting, positioning, and mating surfaces, increasing transmission efficiency (if bolts were used to connect the two components, the decreasing bolt preload during use would reduce friction, potentially causing relative displacement and affecting transmission accuracy).

[0298] 2. The deceleration device 3 adopts a three-stage deceleration, which reduces one stage compared to existing technologies.

[0299] The first-stage reduction mechanism is a helical gear set, mainly used to connect the power motor and the second-stage reduction mechanism, so that the motor can be arranged on the side of the reduction device 3 to shorten the axial dimension of the reduction device 3 assembly.

[0300] The second-stage reduction mechanism is a planetary reduction mechanism with double planetary gears. This stage has a relatively large transmission ratio, mainly to match the transmission ratio of the first-stage reduction mechanism and meet the overall transmission ratio requirements of the first and second stages. The first-stage transmission ratio is designed to be smaller to reduce the diameter of the first-stage output wheel (the first-stage input wheel 201 needs to have a sufficient number of teeth to match the motor output shaft; at the same speed ratio, the more teeth, the larger the gear diameter. Given that the number of teeth cannot be changed, reducing the gear diameter requires reducing the speed ratio), thus lowering the moment of inertia. The overall radial dimension of the second-stage reduction mechanism is also adapted to be approximately the same as the size of the first-stage output wheel 220. Therefore, the first and second-stage reduction mechanisms are installed within the second housing 102, resulting in high space utilization.

[0301] The third-stage reduction mechanism employs a planetary reduction mechanism with a single-ring gear and planetary gears. The planet carrier and output shaft are integrated into a single design, reducing component size and weight while ensuring connection strength.

[0302] The angular reduction mechanism consists of a steering input mechanism 600 and a third-stage reduction mechanism connected in series. The output wheel of the steering input mechanism is directly designed on the output planetary support of the second-stage reduction mechanism, i.e., the second-stage front support 308.

[0303] The first-stage reduction mechanism, the second-stage reduction mechanism, and the steering input mechanism 600 are installed in a semi-enclosed cavity formed by the second housing 102, the third housing 103, and the main support 105, forming a subsystem, namely the rear reduction section 800. The third-stage reduction mechanism is installed in the first housing 101, forming a semi-enclosed space together with the main support 105, and forming an independent subsystem, namely the front reduction section 700. The front reduction section 700 and the rear reduction section 800 can be pre-assembled separately. The advantages are as follows: 1) Each reduction mechanism is installed separately in two subsystems, eliminating the need for stacking them one level at a time. This reduces the installation space depth, installation difficulty, and housing axial dimensions, lowering machining accuracy requirements and reducing the overall difficulty and cost. 2) The third-stage reduction is a low-speed stage that also bears steering loads, as well as transmitted impacts and vibrations. The load on it is relatively large, requiring sufficient mechanical support. The front reduction section 700 and the rear reduction section 800 are separated by a housing. Power is transmitted through the trapezoidal spline connection on the inner spline 331 of the second- and third-stage connecting splines and the third-stage sun gear 403. The main bracket 105 provides support for the side of the third-stage reduction away from the output shaft, ensuring sufficient support strength and precision for the third-stage reduction mechanism, improving the meshing accuracy of each gear, reducing the wear rate, and simultaneously weakening the transmission of impacts and vibrations from the third-stage reduction mechanism to the first-, second-, and angular reduction mechanisms. 3) Similarly, the first-, second-, and angular reduction mechanisms are enclosed in a closed space, improving their structural support strength and precision, increasing gear meshing accuracy, ensuring the uniformity of load distribution on the gear meshing teeth, and reducing the wear rate of the tooth surface. The inner spline 331 of the second- and third-stage connecting splines is also used to connect with the outer spline 430 of the second- and third-stage connecting splines of the front reduction section 700.

[0304] The output wheel of the first-stage reduction mechanism adopts a split design, consisting of a first-stage output gear base 204 and a first-stage output gear ring 203, and is locked by a third connecting bolt 210 and a spring washer 209. The first-stage output gear base 204 is made of die-cast aluminum alloy, and the first-stage output gear ring 203 is made of forged iron, thereby reducing the weight and rotational inertia of the wheel. Since the wheel rotates at a relatively high speed, the reduction in its rotational inertia makes a significant contribution to controlling the rotational inertia of the entire transmission system.

[0305] 3. The main housing adopts a split design, consisting of three parts: the first housing 101, the second housing 102, and the third housing 103. The outer circle of the third-stage internal gear ring 401 of the third-stage reduction mechanism also participates in the composition and sealing of the outer housing as part of the housing. Each major structural component is sealed using gaskets or sealing rings. The fourth housing 104 is used to close the mounting window provided for the angular reduction mechanism. A rear housing sealing ring 107 is provided between the third housing 103 and the second housing 102.

[0306] The first housing 101 serves as the mounting and fixing hole for the reduction gear 3 and a structural component supporting the output shaft. Due to its high structural strength requirements, it is made of cast iron. The other housings, the second housing 102, the third housing 103, and the fourth housing 104, bear less load and mainly serve a connecting function. Therefore, they are made of cast aluminum. This ensures the minimum housing structural wall thickness while effectively utilizing the material's strength properties, thereby reducing the weight of the housing assembly by about 40%.

[0307] The first housing 101 is provided with steering gear mounting holes. Since the location requirements of these mounting holes vary depending on the vehicle model, several mounting hole configurations need to be designed. This necessitates several different structures for the first housing 101, allowing the second housing 102 to remain in a consistent state. Only the first housing 101 needs to be manufactured with multiple structures, significantly reducing mold costs and consequently lowering the cost of the reduction gear 3. In the third-stage reduction mechanism, the third-stage internal gear ring 401 serves as the fixed gear of the planetary reduction mechanism and also as the intermediate connection between the first housing 101 and the second housing 102. These two functions are integrated into a single structural component, eliminating the need for fixing components and corresponding fixing structures on the housing. This improves structural strength while reducing the radial dimension of this section of the housing, ensuring that the first housing 101 and the second housing 102 maintain essentially the same radial dimension without significant dimensional gradient changes. This improves structural compactness, space utilization, reduces overall weight, and enhances load transmission capacity.

[0308] 4. The motor shaft and the output shaft of the first-stage reduction mechanism are no longer coaxially arranged. An intermediate idler gear is used to adjust the center distance between the motor and the main shaft of the reduction device 3, providing sufficient installation space for the motor. The transmission gears 318 of the first-stage transmission mechanism are arranged parallel to the shaft. The motor is positioned on the side adjacent to the reduction device 3, thereby shortening the axial dimension of the main shaft of the reduction device 3 to meet the axial installation space constraints when mounting on the vehicle. The parallel shaft design in the first-stage transmission mechanism allows for a dual-motor input design architecture, where two motors drive two first-stage input gears, which simultaneously drive the intermediate idler gear, thus realizing the change from a single motor to a dual-motor design while minimizing the overall structural modifications.

[0309] 5. The second-stage reduction mechanism is designed as a double planetary reduction gear. The planetary gears consist of a rear planetary gear 304 and a front planetary gear 305. Because the teeth of the two gears are discontinuous in the axial direction, they cannot be machined as a single unit. Therefore, a split design is adopted. The two gears use hexagonal mating shafts and grooves with an interference fit, and are connected together by press fitting. The rear planetary gear 304 and the front planetary gear 305 are supported by the second-stage planetary axial bearing 315, the second-stage planetary radial bearing 313, the second-stage planetary main bearing 314, and the second-stage planetary shaft 312.

[0310] The planetary carrier of the second-stage reduction mechanism is divided into two parts: the second-stage rear support 307 and the second-stage front support 308. Each support has two corresponding protruding circular boss columns. The column on the second-stage front support 308 is provided with threaded holes. The two supports are connected and positioned by a second-stage support connecting column 309, and then tightened by a second-stage support connecting bolt 311. Compared to existing designs, the axial strength of the support is increased, ensuring that the support does not undergo large deflection axial deformation. The planetary gears and sun gear are constrained by bearings for all degrees of freedom except rotation, preventing radial and axial movement, thus reducing tooth surface wear and lowering operating noise.

[0311] The planetary carrier of the third-stage reduction mechanism also adopts a similar connection design. The difference is that one side of the third-stage support connecting column 414 has a bolt thread for direct threaded connection to the third-stage rear support 404, while the other side has a threaded hole that, after mating with the mating surface of the third-stage front support 405, is locked by bolts. The outer contour of the third-stage support connecting column 414 is hexagonal to facilitate tool clamping during installation. In the third-stage reduction mechanism, the planetary gears and sun gear also constrain all degrees of freedom except rotation. In existing technology, the planetary gears and sun gear do not constrain the axial movement degree of freedom. Therefore, during operation, periodic axial forces can cause gear misalignment and impact, increasing the tooth surface wear rate and increasing operating noise.

[0312] 6. A new coupling structure was designed for the connection between the motor output shaft and the input shaft of the first-stage reduction mechanism. The inner ring 503 of the coupling is press-fitted onto the motor shaft 510 via a spline. Six damping buffer pads 504 are circumferentially arranged on the inner ring 503 of the coupling and are inserted together into the groove on the first-stage input gear 201. The coupling transmits power and dampes impacts and fluctuations by compressing the buffer blocks through circumferential rotation. The damping buffer pads are circumferentially arranged on the motor shaft to reduce the axial connection size. The wiring harness connector sealing gasket 109 is connected to the inner ring 503 of the coupling to support and seal the inner ring 503.

[0313] The above embodiments mainly describe the differences between the various embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. For the sake of brevity, they will not be elaborated here.

[0314] While specific embodiments of this application have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of this application. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of this application. The scope of this application is defined by the appended claims.

Claims

1. A speed reduction device (3), comprising: a three-stage transmission mechanism (10); and the three-stage transmission mechanism (10) comprises a first-stage transmission mechanism (200), a second-stage transmission mechanism (300) and a third-stage transmission mechanism (400); the first-stage transmission mechanism (200) is a gear set structure, the second-stage transmission mechanism (300) is a planetary gear set structure, and the third-stage transmission mechanism (400) is a planetary gear set structure. The speed reduction device (3) further comprises:

2. The reduction gear (3) according to claim 1, wherein a first housing (101) in which the third-stage transmission mechanism (400) is arranged; a second housing (102) in which the first-stage transmission mechanism (200) and the second-stage transmission mechanism (300) are arranged; and the first housing (101) and the second housing (102) are detachably connected, and an input end of the third-stage transmission mechanism (400) and an output end of the second-stage transmission mechanism (300) are detachably connected. An input end of the first-stage transmission mechanism (200) is configured to be connected with a driving motor (501); and an input end of the second-stage transmission mechanism (300) is connected with an output end of the first-stage transmission mechanism (200).

3. The reduction gear (3) according to claim 2, wherein The first-stage transmission mechanism (200) comprises at least a first-stage output gear (220) configured to be connected with the driving motor (501) and configured to be connected with an input end of the second-stage transmission mechanism (300).

4. The reduction gear (3) according to claim 3, wherein The first-stage transmission mechanism (200) further comprises a first-stage key connection mechanism (211) arranged at a middle portion of the first-stage output gear (220), the first-stage key connection mechanism (211) being configured to connect the first-stage output gear (220) and the second-stage transmission mechanism (300).

5. The reduction gear (3) according to claim 4, wherein The second-stage transmission mechanism (300) comprises:

6. A reduction gear (3) as claimed in any one of claims 1 to 5, wherein a second-stage sun gear (303) connected with the first-stage transmission mechanism (200) so that the first-stage transmission mechanism (200) drives the second-stage sun gear (303) to rotate; a plurality of planetary gear assemblies (319) sequentially arranged along a circumferential direction of the second-stage sun gear (303) and respectively meshing with the second-stage sun gear (303); and a second-stage inner ring gear (306) in which the plurality of planetary gear assemblies (319) are at least partially arranged and respectively meshing with the second-stage inner ring gear (306). The second-stage transmission mechanism (300) comprises:

7. The reduction gear (3) according to claim 5, wherein a second-stage sun gear (303) connected with the first-stage key connection mechanism (211) so that the first-stage output gear (220) drives the second-stage sun gear (303) to rotate through the first-stage key connection mechanism (211); a plurality of planetary gear rear gears (304) arranged close to the first-stage transmission mechanism (200) and meshing with the second-stage sun gear (303); and a second-stage inner ring gear (306) in which the plurality of planetary gear assemblies (319) are at least partially arranged and respectively meshing with the second-stage inner ring gear (306). A plurality of front planetary wheels (305) are arranged close to the third-stage transmission mechanism (400), and the front planetary wheels (305) are fixed coaxially opposite to the corresponding rear planetary wheels (304); and A second-stage inner ring gear (306) is fixedly connected with the second housing (102), and the front planetary wheels (305) are arranged in the second-stage inner ring gear (306) and meshed with the second-stage inner ring gear (306).

8. The reduction gear (3) according to claim 7, wherein The rear planetary wheels (304) are provided with connecting grooves (341), and the front planetary wheels (305) are provided with connecting shafts (351) which are inserted into the connecting grooves (341), so as to realize the coaxial opposite fixing of the front planetary wheels (305) and the corresponding rear planetary wheels (304).

9. The reduction gear (3) according to claim 7, wherein The second-stage transmission mechanism (300) further comprises: A second-stage rear support (307) is arranged between the first-stage output wheel (220) and the rear planetary wheels (304); and A second-stage front support (308) is arranged between the front planetary wheels (305) and the third-stage transmission mechanism (400), and the second-stage front support (308) is connected with the second-stage rear support (307).

10. The reduction gear (3) according to claim 9, wherein The second-stage transmission mechanism (300) further comprises a plurality of second-stage support connecting bolts (311) which pass through the rear planetary wheels (304) and the front planetary wheels (305), and the second-stage rear support (307) and the second-stage front support (308) are connected through the second-stage support connecting bolts (311).

11. The reduction gear (3) according to claim 9, wherein A second-stage support radial bearing (301) and a second-stage support axial bearing (302) are arranged between the first-stage output wheel (220) and the second-stage rear support (307), and the first-stage output wheel (220) supports the second-stage rear support (307) to rotate.

12. The reduction gear (3) according to claim 9, wherein A second-stage sun gear bearing (316) is arranged between the second-stage sun gear (303) and the second-stage front support (308), and the second-stage front support (308) supports the second-stage sun gear (303) to rotate.

13. The reduction gear (3) according to claim 9, wherein The second-stage front support (308) is detachably connected with the input end of the third-stage transmission mechanism (400), so that the input end of the third-stage transmission mechanism (10) and the output end of the second-stage transmission mechanism (300) are detachably connected.

14. The reduction gear (3) according to claim 13, wherein The second-stage transmission mechanism (300) comprises: A second-stage key connecting mechanism (317) is arranged in the middle of the second-stage front support (308) and used for connecting the third-stage transmission mechanism (400), so that the second-stage front support (308) is detachably connected with the input end of the third-stage transmission mechanism (400).

15. The reduction gear (3) according to claim 9, wherein The second-stage transmission mechanism (300) further comprises: A transmission tooth (318) is arranged on one side of the second-stage front support (308) facing the third-stage transmission mechanism (400), and the transmission tooth (318) is a double-curve spiral gear or a bevel gear.

16. The reduction gear (3) according to claim 9, wherein Further comprising: A steering input mechanism (600) is used to connect externally a steering device, connect internally the second-stage front support (308), and drive the second-stage front support (308) to rotate.

17. The reduction gear (3) according to claim 16, wherein The axial direction of the steering input mechanism (600) is perpendicular to the axial direction of the second-stage front support (308).

18. The reduction gear (3) according to claim 16, wherein The steering input mechanism (600) comprises: An input shaft (603) is used to connect externally a steering device; A torsion bar (608) has a first end connected to the input shaft (603); An input gear (609) is used to connect the second-stage front support (308), and a second end of the torsion bar (608) is connected to the input gear (609); and An angle sensor (605) is sleeved outside the input shaft (603) and is used to detect the relative rotation angle between the input shaft (603) and the input gear (609).

19. The reduction gear (3) according to claim 18, wherein The input shaft (603) is a hollow shaft, the torsion bar (608) is arranged inside the input shaft (603), and the first end of the torsion bar (608) is connected to the input shaft (603) through an input shaft shaft pin (601).

20. The reduction gear (3) according to claim 18, wherein Further comprising: A main support (105) is arranged between the second-stage transmission mechanism (300) and the third-stage transmission mechanism (400), and the main support (105) is fixedly connected to the second housing (102).

21. The reduction gear (3) according to claim 20, wherein The input gear (609) of the steering input mechanism (600) is engaged with the second-stage front support (308), and the axial end of the input gear (609) is connected to the main support (105).

22. The reduction gear (3) according to claim 20, wherein The third-stage transmission mechanism (400) comprises: A third-stage sun gear (403) is detachably connected to the second-stage front support (308), and the third-stage sun gear (403) can be driven by the second-stage front support (308); A plurality of third-stage planet gears (402) are engaged with the third-stage sun gear (403); and A third-stage inner ring gear (401) is fixedly connected to the first housing (101), and the third-stage planet gears (402) are arranged in the third-stage inner ring gear (401) and engaged with the third-stage inner ring gear (401).

23. The reduction gear (3) according to claim 22, wherein The third-stage sun gear (403) is connected to the second-stage key connection mechanism (317) of the second-stage front support (308) to detachably connect the third-stage sun gear (403) to the second-stage front support (308).

24. The reduction gear (3) according to claim 22, wherein A second-stage support main bearing (310) is arranged between the second-stage front support (308) and the main support (105); A third-stage sun gear main bearing (409) is arranged between the main support (105) and the third-stage sun gear (403), and the main support (105) supports the third-stage sun gear (403) to rotate.

25. The reduction gear (3) according to claim 22, wherein The third-stage transmission mechanism (400) further comprises: A third-stage rear support (404) arranged between the second-stage transmission mechanism (300) and the third-stage planetary gear (402); A third-stage front support (405) arranged at an output end of the third-stage transmission mechanism (400), and the third-stage front support (405) is fixedly connected with the third-stage rear support (404); and An output shaft (416) connected with the third-stage front support (405) and capable of being driven to rotate by the third-stage front support (405).

26. The reduction gear (3) according to claim 25, wherein The third-stage transmission mechanism (400) further comprises: A third-stage planetary bearing (407) arranged in the third-stage planetary gear (402); and A third-stage planetary shaft (406) arranged in the third-stage planetary bearing (407) and supporting the third-stage planetary bearing (407) to rotate.

27. The reduction gear (3) according to claim 26, wherein A first end of the third-stage planetary shaft (406) is connected with the third-stage rear support (404), and a second end of the third-stage planetary shaft (406) is connected with the third-stage front support (405), thereby fixedly connecting the third-stage front support (405) with the third-stage rear support (404).

28. The reduction gear (3) according to claim 25, wherein A third-stage rear support main bearing (408) is arranged between the main support (105) and the third-stage rear support (404); An output shaft secondary bearing (410) is arranged between the third-stage sun gear (403) and the third-stage front support (405); and An output shaft main bearing (411) is arranged between the third-stage front support (405) and the first housing (101).

29. The reduction gear (3) according to claim 22, wherein The third-stage inner ring (401) and the first housing (101) are in an integral structure.

30. The reduction gear (3) according to claim 7, wherein Further comprising: A third housing (103) detachably connected with the second housing (102), and the primary output gear (220) is supported by the third housing (103) to rotate.

31. The reduction gear (3) according to claim 30, wherein The primary output gear (220) comprises: A primary output gear ring (203) for connecting a motor control mechanism (500); and A primary output gear machine base body (204) fixedly connected with the primary output gear ring (203), and the primary output gear machine base body (204) is used for connecting the third housing (103) and the second-stage sun gear (303) respectively.

32. The reduction gear (3) according to claim 31, wherein The primary key connection mechanism (211) is arranged at a middle part of the primary output gear machine base body (204).

33. The reduction gear (3) according to claim 32, wherein A primary output gear main bearing (208) is arranged between the third housing (103) and the primary output gear machine base body (204), and the third housing (103) supports the primary output gear (220) to rotate.

34. The reduction gear (3) according to any one of claims 4 to 33, wherein The first-stage transmission mechanism (200) includes a first-stage idler wheel (202) and a first-stage input gear (201). The first-stage idler wheel (202) meshes with the first-stage output wheel (220), and the first-stage input gear (201) meshes with the first-stage idler wheel (202). The first-stage input gear (201) is used to connect to the motor control mechanism (500).

35. The reduction gear (3) according to claim 34, wherein The first-stage transmission mechanism (200) includes two first-stage idler gears (202) and two first-stage input gears (201). The two first-stage idler gears (202) mesh with the first-stage output gear (220) respectively, and the two first-stage input gears (201) mesh with the two first-stage idler gears (202) in a one-to-one correspondence.

36. The reduction gear (3) according to claim 34, wherein The two primary input gears (201) are used to connect the two motor control mechanisms (500) in a one-to-one correspondence; or, The two primary input gears (201) are used to connect to one of the motor control mechanisms (500).

37. A reduction gear (3) according to any one of claims 4 to 33, wherein The first-stage transmission mechanism (200) includes a first-stage input gear (201), which meshes with the first-stage output wheel (220). The first-stage input gear (201) is used to connect to the motor control mechanism (500).

38. The reduction gear (3) according to any one of claims 4 to 33, wherein The first-stage transmission mechanism (200) includes one first-stage idler gear (202) and two first-stage input gears (201), with the two first-stage input gears (201) respectively meshing with one first-stage idler gear (202).

39. A reduction gear (3) according to any one of claims 4 to 33, wherein The first-stage output wheel (220) is a worm gear or a helical gear.

40. The reduction gear (3) according to any one of claims 1 to 33, wherein The second-stage transmission mechanism (300) is a harmonic reduction mechanism, a rotary vector reduction mechanism, or a pinwheel reduction mechanism; and / or, The third-stage transmission mechanism (400) is a harmonic deceleration mechanism, a rotary vector deceleration mechanism, or a pinwheel deceleration mechanism.

41. A power steering gear (2) comprising: The speed reduction device (3) according to any one of claims 1 to 40; The motor control mechanism (500) is connected to the first-stage transmission mechanism (200) of the speed reduction device (3) and is used to drive the first-stage transmission mechanism (200) of the speed reduction device (3) to rotate.

42. A power steering gear (2) according to claim 41 wherein, The motor control mechanism (500) includes: One or two drive motors (501), each drive motor (501) including a motor shaft (510) connected to the first-stage transmission mechanism (200); and The drive motor (501) is fixedly connected to the second housing (102) of the reduction device (3).

43. A power assisted steering gear (2) according to claim 42 wherein, The motor control mechanism (500) also includes: The inner ring (503) of the coupling is connected to the motor shaft (510) and the first-stage input gear (201) of the reduction gear (3); and A damping buffer pad (504) is disposed between the inner ring (503) of the coupling and the first-stage input gear (201).

44. A vehicle (1) comprising a power steering system (2) according to any one of claims 41 to 43.

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